/*
 * EConcurrentListIterator.hh
 *
 *  Created on: 2014-8-12
 *      Author: cxxjava@163.com
 */

#ifndef ECONCURRENTLISTITERATOR_HH_
#define ECONCURRENTLISTITERATOR_HH_

#include "EConcurrentIterator.hh"

namespace efc {

/**
 * An iterator for lists that allows the programmer
 * to traverse the list in either direction, modify
 * the list during iteration, and obtain the iterator's
 * current position in the list. A {@code ListIterator}
 * has no current element; its <I>cursor position</I> always
 * lies between the element that would be returned by a call
 * to {@code previous()} and the element that would be
 * returned by a call to {@code next()}.
 * An iterator for a list of length {@code n} has {@code n+1} possible
 * cursor positions, as illustrated by the carets ({@code ^}) below:
 * <PRE>
 *                      Element(0)   Element(1)   Element(2)   ... Element(n-1)
 * cursor positions:  ^            ^            ^            ^                  ^
 * </PRE>
 * Note that the {@link #remove} and {@link #set(Object)} methods are
 * <i>not</i> defined in terms of the cursor position;  they are defined to
 * operate on the last element returned by a call to {@link #next} or
 * {@link #previous()}.
 *
 * <p>This interface is a member of the
 * <a href="{@docRoot}/../technotes/guides/collections/index.html">
 * Java Collections Framework</a>.
 *
 * @see Collection
 * @see List
 * @see Iterator
 * @see Enumeration
 * @see List#listIterator()
 * @since   1.2
 */

template<typename E>
interface EConcurrentListIterator: public EConcurrentIterator<E>
{
	virtual ~EConcurrentListIterator(){}

	// Query Operations

	/**
	 * Returns {@code true} if this list iterator has more elements when
	 * traversing the list in the forward direction. (In other words,
	 * returns {@code true} if {@link #next} would return an element rather
	 * than throwing an exception.)
	 *
	 * @return {@code true} if the list iterator has more elements when
	 *         traversing the list in the forward direction
	 */
	virtual boolean hasNext() = 0;

	/**
	 * Returns the next element in the list and advances the cursor position.
	 * This method may be called repeatedly to iterate through the list,
	 * or intermixed with calls to {@link #previous} to go back and forth.
	 * (Note that alternating calls to {@code next} and {@code previous}
	 * will return the same element repeatedly.)
	 *
	 * @return the next element in the list
	 * @throws NoSuchElementException if the iteration has no next element
	 */
	virtual sp<E> next() = 0;

	/**
	 * Returns {@code true} if this list iterator has more elements when
	 * traversing the list in the reverse direction.  (In other words,
	 * returns {@code true} if {@link #previous} would return an element
	 * rather than throwing an exception.)
	 *
	 * @return {@code true} if the list iterator has more elements when
	 *         traversing the list in the reverse direction
	 */
	virtual boolean hasPrevious() = 0;

	/**
	 * Returns the previous element in the list and moves the cursor
	 * position backwards.  This method may be called repeatedly to
	 * iterate through the list backwards, or intermixed with calls to
	 * {@link #next} to go back and forth.  (Note that alternating calls
	 * to {@code next} and {@code previous} will return the same
	 * element repeatedly.)
	 *
	 * @return the previous element in the list
	 * @throws NoSuchElementException if the iteration has no previous
	 *         element
	 */
	virtual sp<E> previous() = 0;

	/**
	 * Returns the index of the element that would be returned by a
	 * subsequent call to {@link #next}. (Returns list size if the list
	 * iterator is at the end of the list.)
	 *
	 * @return the index of the element that would be returned by a
	 *         subsequent call to {@code next}, or list size if the list
	 *         iterator is at the end of the list
	 */
	virtual int nextIndex() = 0;

	/**
	 * Returns the index of the element that would be returned by a
	 * subsequent call to {@link #previous}. (Returns -1 if the list
	 * iterator is at the beginning of the list.)
	 *
	 * @return the index of the element that would be returned by a
	 *         subsequent call to {@code previous}, or -1 if the list
	 *         iterator is at the beginning of the list
	 */
	virtual int previousIndex() = 0;

	// Modification Operations

	/**
	 * Removes from the list the last element that was returned by {@link
	 * #next} or {@link #previous} (optional operation).  This call can
	 * only be made once per call to {@code next} or {@code previous}.
	 * It can be made only if {@link #add} has not been
	 * called after the last call to {@code next} or {@code previous}.
	 *
	 * @throws UnsupportedOperationException if the {@code remove}
	 *         operation is not supported by this list iterator
	 * @throws IllegalStateException if neither {@code next} nor
	 *         {@code previous} have been called, or {@code remove} or
	 *         {@code add} have been called after the last call to
	 *         {@code next} or {@code previous}
	 */
	virtual void remove() = 0;

	/**
	 * Replaces the last element returned by {@link #next} or
	 * {@link #previous} with the specified element (optional operation).
	 * This call can be made only if neither {@link #remove} nor {@link
	 * #add} have been called after the last call to {@code next} or
	 * {@code previous}.
	 *
	 * @param e the element with which to replace the last element returned by
	 *          {@code next} or {@code previous}
	 * @throws UnsupportedOperationException if the {@code set} operation
	 *         is not supported by this list iterator
	 * @throws ClassCastException if the class of the specified element
	 *         prevents it from being added to this list
	 * @throws IllegalArgumentException if some aspect of the specified
	 *         element prevents it from being added to this list
	 * @throws IllegalStateException if neither {@code next} nor
	 *         {@code previous} have been called, or {@code remove} or
	 *         {@code add} have been called after the last call to
	 *         {@code next} or {@code previous}
	 */
	virtual void set(sp<E> e) = 0;

	/**
	 * Inserts the specified element into the list (optional operation).
	 * The element is inserted immediately before the next element that
	 * would be returned by {@link #next}, if any, and after the next
	 * element that would be returned by {@link #previous}, if any.  (If the
	 * list contains no elements, the new element becomes the sole element
	 * on the list.)  The new element is inserted before the implicit
	 * cursor: a subsequent call to {@code next} would be unaffected, and a
	 * subsequent call to {@code previous} would return the new element.
	 * (This call increases by one the value that would be returned by a
	 * call to {@code nextIndex} or {@code previousIndex}.)
	 *
	 * @param e the element to insert
	 * @throws UnsupportedOperationException if the {@code add} method is
	 *         not supported by this list iterator
	 * @throws ClassCastException if the class of the specified element
	 *         prevents it from being added to this list
	 * @throws IllegalArgumentException if some aspect of this element
	 *         prevents it from being added to this list
	 */
	virtual void add(sp<E> e) = 0;
};

} /* namespace efc */
#endif /* ECONCURRENTLISTITERATOR_HH_ */
